UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL    EXPERIMENT   STATION 

/.«..-«-    ^-     .__.*.. .._..__  BENJ.   IDE   WHEELER,    President 

COLLEGE   OF   AGR  CULTURE 

&     VF     MVaPI,v',-',-,  ur,c-  THOMAS    FORSYTH    H  U  NT,    DEAN  AN  D   DIRECTOR 

BERKELEY  h.  e.  van  norman,  vice-director  and  dean 

University  Farm  School 


CIRCULAR  No.  194 
February,  1918 


INTERCROPPING   OF   YOUNG 
IRRIGATED   ORCHARDS 

By  E.  S.  VAILE 


More  California  orchards  were  intercropped  during  1917  than  ever 
before.  The  desire  to  produce  more  actual  food  during  the  present 
war  emergency,  and  the  added  desire  to  share  in  the  prevailing  high 
prices  contributed  to  this  result.  An  exhaustive  survey,  made  through 
the  agencies  of  the  various  marketing  associations,  the  County  Horti- 
cultural Commissioners,  and  Farm  Advisors,  indicates  that  where 
normally  only  about  25  per  cent  of  the  irrigated  orchards  under  six 
years  of  age  are  intercropped;  this  year,  1917,  at  least  45  per  cent 
have  been  so  handled.  Going  more  into  detail,  the  percentage  of 
orchards,  three  years  old  and  under,  intercropped  has  increased  from 
33  per  cent  to  50  per  cent,  while  the  percentage  of  intercropped 
orchards  from  three  to  six  years  of  age  has  increased  from  20  per  cent 
to  40  per  cent. 

The  survey  indicates  that  out  of  some  77,000  orchard  acres  of 
young  citrus  in  southern  California  30,000  acres  have  been  planted 
to  beans,  3000  to  grain  sorghums,  1000  to  corn,  2000  to  potatoes.,  and 
one  or  two  thousand  to  miscellaneous  crops.  About  the  same  per- 
centage holds  for  the  irrigated  deciduous  orchards  of  southern  Cali- 
fornia and  very  nearly  the  same  ratio  of  crops  used.  In  the  San 
Joaquin  Valley  the  amount  of  intercropping  is  not  so  large  and  grain 
sorghums  occupy  almost  an  equal  place  with  beans. 

This  paper  is  based  on  a  field  study  of,  first,  the  results  obtained 
with  the  increase  in  intercropping,  and  second,  the  possibilities  of  even 
further  extension  in  the  future.  Young  orchards  only  are  considered. 
The  intercropping  of  bearing  orchards  is  a  practice  which  has  been 
dismissed    in    the    past    as   being    both    agriculturally   unsound    and 


financially  unprofitable,  under  the  ordinary  California  orchard  con- 
ditions. The  evidence  seems  conclusive  that  there  is  nothing  in  the 
present  situation  to  justify  a  change  in  this  general  attitude. 

The  intercropping  of  unirrigated  orchards  is  too  hazardous  for 
consideration,  both  agriculturally  and  financially,  except  in  a  few 
locations  where  the  minimum  rainfall  is  sufficient  to  insure  satis- 
faction to  both  crops. 

ECONOMIC   ADVANTAGES 

The  man  who  is  intercropping  an  irrigated  orchard  has  certain 
very  definite  economic  advantages  over  the  man  who  is  raising  a  crop 
in  an  open  field ;  namely : 

1.  The  orchard  pays  the  land  rental  charges  including  interest 
and  taxes ;  the  intercrop  does  not  have  to  meet  that  expense. 

2.  The  usual  practice  in  irrigated  orchards  that  are  not  inter- 
cropped is  to  work  up  the  land  thoroughly  in  the  spring  and  keep  it 
cultivated  during  the  summer;  thus  the  intercrop  need  not  pay  the 
expense  of  preparing  the  land  for  planting. 

3.  The  arrangement  of  many  irrigation  projects  provides  for  the 
delivery  of  sufficient  water  to  support  full  bearing  orchard  trees; 
there  is  no  saving  in  cash  payments  for  water  in  certain  cases  if  less 
than  the  total  amount  is  used  ;  it  takes  no  more  water  to  care  for  young 
trees  and  an  intercrop  than  it  does  for  full  bearing  trees ;  therefore, 
in  these  cases  the  water  for  irrigating  the  intercrop  is  not  properly 
chargeable  to  that  crop. 

4.  Very  often  orchardists  have  unused  time  of  both  themselves 
and  their  teams,  which  can  be  turned  to  good  service  in  the  planting 
and  care  of  the  intercrop ;  in  which  case  the  entire  labor  cost  is  not 
properly  chargeable  to  the  intercrop. 

In  other  words,  the  additional  expenditures  connected  with  inter- 
cropping orchards,  are  mainly  reduced  to  the  cost  of  seed,  a  possible 
slight  charge  for  cultivation  during  the  growing  season,  the  harvesting 
costs  and,  sometimes,  a  charge  for  additional  water. 

LIMITING    FACTORS 

On  the  other  hand,  intercropping  is  by  no  means  a  "get  rich 
quick"  scheme.  Success  with  intercropping  depends  upon  how  and 
under  what  conditions  it  is  done.  No  crop,  whether  an  intercrop  or 
one  in  the  open  field,  can  be  better  than  that  allowed  by  the  weakest 
of  several  factors  necessary  to  its  production,  namely:  the  farmer; 
the  soil ;  the  climate ;  the  moisture  supply.     The  first  requirement, 


therefore,  is  to  choose  that  crop  which  the  farmer  himself  knows  some- 
thing about.  As  a  secondary  consideration,  this  crop  must  be  adapted 
to  the  soil  and  climatic  conditions  under  which  he  is  working ;  and  an 
abundant  moisture  supply  both  for  the  intercrop  and  the  trees  must 
be  assured.  An  off  season  may  even  then  result  in  partial  or  total 
crop  loss. 

The  point  which  most  often  leads  to  failure  with  intercropping  is 
the  fact  that  the  grower  overlooks  the  necessity  of  caring  for  each  of 
the  two  crops  just  as  religiously  as  though  it  were  growing  alone.  If 
this  is  not  done,  one  or  the  other  crop  is  sure  to  suffer. 

Certain  crops,  particularly  the  cereals,  are  notably  hard  in  their 
effects  on  soil  productivity.  When  they  are  used  as  intercrops,  there- 
fore, more  than  the  usual  amends  must  be  made.  With  grain  hays 
the  soil  is  frequently  allowed  to  become  excessively  dry  just  at  the 
time  of  ripening  of  the  hay.  Orchards  are  very  apt  to  suffer  because 
of  this  factor.  Grain  stubble  left  standing  in  the  field  during  the  hot 
weather  of  early  summer  is  liable  to  cause  severe  sunburning  of 
orchard  trees,  apparently  through  the  intense  heat  reflected,  as  well 
as  because  of  excessive  drying  out  of  the  soil. 

Harvesting  of  various  crops  is  apt  to  interfere  with  orchard  work, 
both  in  point  of  time  and  by  enforced  tramping  of  wet  ground. 

At  present  the  market  will  hardly  be  a  limiting  factor  except  in 
case  of  less  than  car  lots  of  perishables.  Non-perishables  and  car  lot 
shipments  can  always  be  disposed  of  at  better  than  pre-war  prices. 

IMPORTANT  CONSIDERATIONS 

There  are  three  especially  important  considerations  in  the  inter- 
cropping of  young  orchards;  namely: 

1.  The  maintenance  of  the  productive  condition  of  the  soil; 

2.  The  financial  returns  from  the  crop ; 

3.  The  distribution  of  labor  between  the  orchard  work  and  the 
intererop. 

MAINTENANCE  OF  THE  PRODUCTIVE  CONDITION  OF  THE  SOIL 

In  considering  these  points  it  is  necessary  to  keep  in  mind  the  fact 
that  all  of  our  semi-arid  irrigated  land  is  confronted  by  the  very 
serious  problem  of  maintaining  the  organic  matter  of  soils.  Just  at 
present,  there  is  a  rapid  decrease  in  the  available  supply  of  barnyard 
manure,  and  also  a  growing  tendency  on  the  part  of  bean  growers  to 
utilize  bean  straw  directly  on  their  own  land.  The  value  of  alfalfa 
hay  and  even  cereal  straw  for  feeding  purposes  is  so  high  now  as  to 


be  almost  prohibitive  for  soil  improvement  purposes.  Therefore,  it 
seems  particularly  desirable  that  leguminous  green  manure  crops  be 
used  in  all  orchards.  In  other  words,  intercropping  should  not  inter- 
fere with  the  common  practice  of  raising  a  winter  green  manure  crop 
which  ma}'  be  plowed  under  in  the  early  spring.  Summer  green 
manure  crops  may  occasionally  be  substituted  in  cases  where  winter 
crops  such  as  cabbage  are  distinctly  the  most  profitable  cash  crops 
which  could  be  grown  on  the  land.  Ample  water  for  the  summer 
green  manure  crop  would  need  to  be  assured  in  such  cases. 

The  organic  matter  problem  immediate^  suggests  the  possibility 
of  growing  a  strip  of  alfalfa  between  the  young  trees  for  a  period  of 
years,  a  part  of  which  may  be  used  for  soil  improvement  around  the 
trees.  This  is  entirely  feasible  on  well  drained  soils  where  ample 
water  is  available.  Ample  water  in  this  conection  will  usually  mean 
irrigation  once  every  two  weeks  through  the  growing  season,  with  a 
total  of  at  least  50  per  cent  more  water  than  would  be  used  on  the 
same  soil  for  the  trees  and  an  intercrop  of  beans.  Trees  growing  on 
heavy,  poorly  drained  soil  have  frequently  shown  injury  from  the 
large  applications  of  water  used  on  the  alfalfa  and  therefore,  great 
caution  must  be  exercised  with  this  combination  planting. 

Beans,  corn,  sorghum,  potatoes,  and  many  of  the  short  seasoned 
vegetable  crops  may  be  raised  during  the  summer  without  interfering 
with  winter  green  manuring. 

The  immediate  effect  of  intercropping  on  the  growth  and  appear- 
ance of  orchard  trees  may  be  taken  as  indicative  of  the  effect  on  soil 
conditions.  This  effect  may  appear  as  an  actual  improvement  in  the 
trees,  showing  that  the  practice  need  in  no  way  interfere  with  the 
yield  or  development  of  the  orchard,  provided  the  proper  crop  and 
the  proper  system  of  management  are  undertaken.  Out  of  several 
hundred  inquiries,  no  one  was  found  who  felt  that  beans,  for  instance, 
injured  young  trees  when  grown  as  an  intercrop.  Several  felt  that 
they  would  not  plant  beans,  particularly  in  the  San  Joaquin  Valley, 
because  they  felt  there  was  too  small  a  margin  of  profit  in  the  under- 
taking, not  because  of  interference  with  tree  growth.  In  fact  the  ex- 
perience of  years  in  commercial  bean  growing  in  California  indicates 
that  the  soil  is  not  noticeably  injured  for  a  long  period  of  time,  par- 
ticularly if  the  bean  straw  is  returned  to  the  soil  and  many  growers 
feel  that  the  land  is  actually  improved  by  the  cultural  methods  neces- 
sary for  good  bean  production. 

Numerous  instances  were  found  where  other  crops  than  beans 
showed  an  immediate  effect  upon  tree  appearance  and  growth.     A 


study  of  such  cases  indicates  three  principal  factors  contributing  to 
this  effect ;  namely,  competition  for  nitrogen ;  competition  for  moist- 
ure ;  and  puddling  of  the  soil.  The  evidence  seems  perfectly  clear  that 
the  first  two  of  these  factors  can  be  overcome  by  avoiding  planting 
too  close  to  the  trees  and  by  maintaining  an  ample  moisture  supply 
in  the  uncropped  strip  near  the  trees.  The  exact  distance  at  which  it 
is  safe  to  plant  cannot  be  given.  Local  experience  and  the  best  judg- 
ment of  the  farmer  must  dictate  that.  Give  the  benefit  to  the  tree 
rather  than  to  the  intercrop,  when  in  doubt.  The  third  factor  may  be 
avoided  by  not  planting  crops  which  require  tramping  of  the  ground 
when  it  is  wet. 


FINANCIAL  EETURNS 

It  is  impossible  to  discuss  the  question  of  cash  returns  without 
presupposing  a  definite  yield.  The  yield  will  vary  with  the  condition 
under  which  the  crop  is  grown.  For  certain  sections  of  the  state, 
potatoes  will  give  the  largest  cash  return,  while  in  other  cases  it  will 
be  beans  and  in  a  few  cases,  corn  or  grain  sorghum.  It  is  even  more 
difficult  to  consider  the  cash  returns  that  might  come  from  vegetable 
growing,  because  in  that  particular  case  the  skill  of  the  farmer  is  of 
importance  out  of  all  proportion  to  any  other  factor. 

A  few  illustrations  may  be  taken  from  this  year's  experience  with 
intercropping  of  young  orchards  which  will  indicate  the  possibilities. 
A  certain  farmer  in  the  Yucaipa  Valley  who  was  an  experienced  potato 
grower  intercropped  a  considerable  acreage  of  young  apple  orchards 
with  potatoes.  He  had  one-half  to  three-eighths  of  the  land  in 
potatoes,  thus  leaving  a  considerable  strip  along  the  tree  rows  as  a 
protection  against  injury  to  the  trees.  He  harvested  an  average  of 
110  sacks  per  orchard  acre,  which  he  sold  at  $3.00  a  sack.  His  extra 
water  cost  was  $1.00  per  acre.  His  only  other  extra  costs  were  seeding, 
cultivation  of  the  potatoes  and  the  harvesting,  which  were,  of  course, 
not  higher  than  similar  costs  would  be  on  open  ground.  A  certain 
farmer  in  the  cabbage  section  in  Orange  County  grew  last  winter  five 
tons  of  winter  cabbage  to  the  orchard  acre.  Following  the  harvesting 
of  the  cabbage,  he  planted  Black  Eye  beans  in  late  June  and  harvested 
twelve  sacks  per  orchard  acre.  His  gross  returns  were  approximately 
$150  per  acre.  The  owner  of  a  young  walnut  orchard  in  Ventura 
County  has  for  the  past  two  years  raised  3000  pounds  of  Henderson 
bush  limas  per  orchard  acre.  This  year  he  sold  his  beans  for  12c  a 
pound,  or  a  gross  return  of  $360  per  orchard  acre.     A  walnut  grower 


in  El  Monte  turned  under  a  green  manure  crop  in  February,  1917. 
In  June,  he  harvested  seventy-five  sacks  of  potatoes  and  in  October  he 
threshed  twelve  sacks  of  Black  Eye  beans  to  the  orchard  acre.  Total 
gross  returns  about  $260  per  acre.  In  a  two-year-old  citrus  orchard 
near  Santa  Ana,  the  owner  raised  sweet  potatoes  which  he  sold  for  $400 
per  orchard  acre  yield.  These  followed  a  winter  green  manure  crop, 
but  they  were  matured  early  so  as  to  take  advantage  of  high  prices. 
These  are,  of  course,  the  results  obtained  by  particularly  good  farmers 
working  under  favorable  conditions. 

A  summary  of  the  records  of  yields  of  intercropped  citrus  land, 
covering  several  hundred  individual  instances,  shows  that  one  should 
expect  from  an  orchard  acre  of  three-year-old  trees  or  younger, 
60  per  cent  of  the  yield  which  he  would  get  from  an  open  field  acre 
under  like  soil  and  climatic  conditions,  and  50  per  cent  of  a  normal 
open  field  yield  in  orchards  from  four  to  six  years  of  age,  inclusive. 
Walnut  groves  will  do  better  than  this  because  of  the  great  distance 
between  the  slow  growing  trees.  A  50  per  cent  yield  may  often  be 
obtained  in  a  ten-year-old  orchard  where  the  trees  are  sixty  feet  apart. 
Plantings  in  apricot  orchards,  on  the  other  hand,  will  not  do  so  well 
as  those  in  citrus.  In  fact,  intercropping  probably  will  not  be  profit- 
able after  the  apricot  trees  are  four  years  old. 


RESULTS  AT  CITRUS  EXPERIMENT  STATION  FARM 

The  following  statement  of  the  results  with  intercropping  sixty 
acres  of  the  Citrus  Experiment  Station  property  at  Riverside  with 
Black  Eye  beans  many  be  taken  as  typical  of  what  may  be  accomplished 
even  when  conditions  are  below  normal  to  begin  with. 

The  laud  in  question  had  been  cropped  to  grain  hay  for  many  years.  So  far 
as  known,  it  had  never  been  planted  to  any  other  crop  prior  to  this  year,  nor  had 
it  ever  been  irrigated.  In  1915,  one  ton  of  oats  per  acre  was  harvested  from  a 
part  of  the  tract,  the  remainder  being  untilled  that  season.  Following  this  crop, 
all  the  land  was  deeply  plowed  and  nothing  was  planted  during  1916. 

The  property  was  planted  to  citrus  trees  during  the  months  of  May  and  June, 
1917,  with  the  trees  placed  20  X  24  feet  apart.  A  narrow  strip  of  land  in  the  tree 
row  was  plowed  at  the  time  of  planting.  The  rest  of  the  ground  was  unworked 
until  preparation  for  bean  planting  was  commenced. 

For  bean  growing,  the  land  was  double-disced  with  tractor  and  12-inch  disc 
two  ways  and  harrowed;  four  and  one-half  acre  inches  of  water  was  applied  in 
furrows  fourteen  inches  apart;  the  land  was  double-disced  again  and  seed  planted. 
The  seed  was  planted  with  bean  planter,  rows  being  thirty-six  inches  apart,  with 
six  rows  between  the  trees,  occupying  three-fourths  of  the  ground.  The  dates  of 
planting  were  from  June  7  to  26. 


7 

Two  irrigations  were  necessary  after  planting,  one,  July  23,  and  one,  August 
15.  Cultivation  was  done  with  a  modified  Planet  Jr.  cultivator,  having  two  sweeps 
to  the  row  and  cultivating  two  rows  at  a  time. 

In  addition  to  the  beans,  a  single  row  of  dwarf  milo  was  grown  in  the  tree 
rows.  The  heads  have  been  harvested  and  the  stalks  used  to  tie  up  the  trees  as  a 
prevention  of  frost  injury  during  the  winter.  The  grain  produced  will  easily  pay 
for  the  cost  of  growing  the  sorghum  and  tieing  the  trees 


Cost  of  EaisinOt  Crop  of  Black  Eye  Beans  at  Citrus  Experiment  Station,  1917 

Orchard  acre  Full 

(J  of  an  acre)  acre 
Preparing  Land 

Double-disced  and  harrowed  two  ways   (tractor)  $  .68  $  .90 

Seed 

18  pounds  @   12V2c 2.25  3.00 

Planting 

Two    row   bean   planter .27  .36 

Irrigations 

4%  acre  inches — one  full  acre  @  30c  per  acre 

inch $1.35 

Labor  of  irrigating .37 

Cost  of  one  irrigation,  per  acre $1.72 

Total  of  three  irrigations,  one  before  and  two  after 

planting    3.87  5.16 

Cultivation 

Furrowing  for  irrigations   (three),  32c  per  acre .96  1.26 

Cultivations    (three)    @   36c 1.08  1.44 

Hoeing 

One  hoeing  @  10c 08  .10 

Cutting 

Twelve   orchard  acres  per   day,  one  man,  two   horses, 

$4.00  33  .44 

Bunching  Beans 

Three  men,  twelve  acres  per  day,  @  $7.50 63  .84 

Hauling  to  stack 80  1.07 

Feeding  from  stack  to  thresher 31  .41 

Threshing 

7%  sacks  per  acre  @  35c  per  sack 2.63  3.51 

Cleaning  charges 

New  sacks  and  stencilling,  7%  sacks  per  acre  @  15c 

per  sack  : 1.12  1.50 

Cleaning  @  lie  per  100  lbs. — 595  lbs 65  .87 


Orchard  acre  Full 

(^  of  an  acre)  acre 
Freight  to  cleaning  house 

595  lbs.  @  $2.15  per  ton 07  .09 


Total   cost   $15.73 

Credit,  540  lbs.  beans  @  8%c 45.90 

19  lbs.  split  beans  @  iy2 29 


$46.19 
Less  cost  15.73 


$20.95 

61.20 

.39 

$61.59 
20.95 

Net    profit    $30.4;i  $40.64 

The  only  orchard  costs  for  the  period  June  7  to  September   17,  not  charged 
directly  to  the  bean  crop,  were  as  follows: 

Water  for  the  trees,  8  acre  inches  @  30c * $2.40 

Cultivation  for  trees,  including  furrowing  out,  one  horse  Avork 1.65 


Total   per    acre $4.05 

It  should  be  borne  in  mind  that  had  these  beans  sold  for  4c  (a  good  pre-war 
price  for  Black  Eye  beans)  the  gross  returns  would  have  been  only  $21.60,  and 
tbe  net  profit  $5.87.  Even  this  would  have  paid  all  the  other  orchard  costs  for  the 
summer  and  left  $1.87  per  orchard  acre  as  a  margin  of  net  profit.  On  the  other 
hand,  the  cost  of  $4.05  per  acre,  charged  against  the  trees  might  have  been 
increased  somewhat  had  the  grove  been  clean  cultivated. 


ADJUSTMENT  OF  LABOE  REQUIREMENTS 

Choice  of  intercrops  should  be  made  with  due  consideration  to  the 
labor  requirements  of  both  the  orchard  and  the  intercrop.  For  in- 
stance, the  planting  of  the  intercrop  should  be  so  planned  that  the 
supply  of  man  and  horse  power  at  hand  may  be  turned  directly  from 
the  rush  of  spring  orchard  work  to  the  preparation  of  land  and  plant- 
ing. Similarly,  the  time  for  harvesting  the  intercrop  should  be 
planned  to  avoid  the  stress  of  fruit  harvest  so  far  as  possible.  Much 
of  the  work  connected  with  the  intercrop  may  be  handled  by  the 
regular  labor  supply  in  time  which  might  not  otherwise  be  gainfully 
employed,  unless  such  coordination  is  worked  out.  Black  Eye  beans 
may  be  planted,  in  the  interior  localities  at  least,  any  time  from  the 
middle  of  May  to  the  first  of  July,  with  every  reason  to  expect  a  satis- 
factory harvest.  The  time  of  maturing  in  the  interior  is  about  ninety 
days  on  the  average.  The  following  table  gives  the  planting  and  har- 
vesting dates  of  Black  Eye  beans  on  the  Citrus  Experiment  Station 
farm  at  Riverside,  1917  season. 


Effect  of  Different  Dates  of  Planting  on  Growing  Days  of 
Black  Eye  Beans 

Planting  Cutting  Days  E'irst  Dates 

date  date  growing  irrigation  irrigated 

May  12-14  Aug.   20  100  Early   in   July 


June     7-8  Sept.     3  88  July  25-28  Aug.  15,16 

June  22  Sept.  16  86  July  23-28               4        Aug.  22-24 

June  26  Sept.  19  85  July  29  Aug.  27 

June  28  Sept.  21  85  Aug.     1-2  Aug.  30-31 

July   10  Oct.       2  84  Aug.  10  Sept.    5 

July   19  Oct.       9  82  Aug.     3 
Average  of  season's  planting,  87  days. 

Potatoes,  if  planted  for  the  spring  crop,  should  be  in  the  ground 
before  the  10th  of  March,  and  may  then  be  harvested  by  the  middle 
of  June.  This  means  a  rush  of  work  following  the  turning  under  of 
the  cover  crop.  Fall  potatoes  are  apt  to  compete  in  point  of  time  with 
the  proper  planting  of  a  winter  cover  crop  following  their  harvest. 

DISCUSSION   OF  CROPS 

As  mentioned  in  the  introduction,  beans,  grain  sorghum  and  pota- 
toes have  been  the  principal  intercrops  used  during  the  past  season, 
with  beans  easily  the  favorite.  Some  of  the  advantages  and  require- 
ments of  these  crops  have  been  mentioned  in  illustration  of  various 
points  relative  to  intercropping.  The  reason  for  the  predominance  of 
beans  may  be  summed  up  briefly  as  follows :  they  are  not  hard  on 
the  soil  and  may  even  be  a  benefit  to  the  orchard ;  the  water  require- 
ments are  easily  met  without  interference  with  orchard  irrigation ;  the 
product  is  non-perishable,  of  high  food  value,  and  can  be  shipped 
anywhere ;  varieties  may  be  found  adapted  to  almost  every  condition 
and  the  cultural  requirements  are,  in  general,  well  understood. 

Spring  potatoes  follow  a  winter  cover  crop  admirably,  provided  the 
labor  requirements  can  be  adjusted.  Usually  no  extra  water  is  re- 
quired for  this  crop,  beyond  what  would  normally  be  used  for  the 
orchard.  As  an  illustration,  American  Wonder  potatoes  were  planted 
on  the  Citrus  Experiment  Station  farm  at  Riverside  in  late  Febru- 
ary, following  the  plowing  down  of  a  Melilotus  crop.  They  were  irri- 
gated twice  and  harvested  in  June,  yielding  125  sacks  per  solid  acre. 
A  crop  of  early  amber  sorghum  followed  the  potatoes  and  was  har- 
vested for  hay  to  make  way  for  another  winter  crop  of  Melilotus.  Fall 
potatoes,  on  the  other  hand,  require  irrigation  at  least  once  every  two 
weeks  for  the  first  six  weeks  after  planting. 


10 

Grain  sorghums  give  good  promise  in  the  interior  sections,  although 
they  are  not  of  equal  cash  value  per  acre  to  either  beans  or  potatoes. 
The  labor  requirements  are  relatively  low,  but  the  growing  season  is 
long  compared  to  that  for  Black  Eye  beans. 


MISCELLANEOUS  CROPS 

There  are  certain  other  crops  which  are  occasionally  used  as  inter- 
crops.   A  few  of  these  will  be  briefly  mentioned. 

Tomatoes  are  desirable  if  the  marketing  facilities  are  good.  Fre- 
quently, however,  unless  there  is  a  cannery  to  absorb  the  surplus,  the 
market  conditions  are  such  that  no  profit  is  realized  from  this  crop. 
There  is  the  injurious  factor  with  tomatoes  of  constantly  tramping 
the  ground  during  the  picking. 

Cantaloupes  may  be  raised,  but  in  most  cases  it  is  impossible  to 
compete  with  the  Imperial  Valley  and  the  Fresno  cantaloupe  sections. 

Casabas  give  a  fair  market  return  but  are  \ery  frequently  ruined 
by  aphis. 

Winter  peas  if  grown  for  the  December  trade  are  always  at  a 
premium  price.  They  have  a  very  high  labor  requirement  at  the  time 
of  picking.  This,  however,  comes  at  a  time  when  orchard  labor  re- 
quirements are  relatively  low.  There  is  the  disadvantage  with  this 
crop  of  tramping  the  ground  while  it  is  wet  during  the  picking 
season.  There  is  the  advantage  that  the  vines  themselves  form  the 
winter  green  manure  crop  following  the  harvesting  of  the  pods.  The 
growing  of  peas  for  the  canneries  is  not  a  feasible  proposition  except 
where  canneries  are  equipped  for  handling  peas  through  the  viner 
method.    Peas  are  subject  to  attacks  of  aphis  and  damage  by  mildew. 

Sweet  potatoes  fit  in  nicety  with  orchard  requirements  where  the 
soil  is  adapted  to  sweet  potato  culture.  This  is  one  of  the  most  profit- 
able crops  in  the  whole  list  of  annuals  in  California,  but  it  is  adapted 
to  a  comparatively  small  range  of  soil  conditions.  Sweet  potatoes  are 
difficult  to  keep  in  storage. 

Vegetable  growing  is  a  specialized  art  and  only  those  familiar 
with  it  are  apt  to  succeed.  Market  conditions  are  often  uncertain 
although  some  things  may  be  sold  on  contract  in  advance  of  growing. 
This  applies  particularly  to  such  crops  as  spinach,  peppers,  and 
tomatoes  for  the  canners.  The  opinion  of  one  very  practical  orchard- 
ist  on  this  point  of  vegetable  growing  is  quoted  as  follows:  "The  list 
of  possible  vegetables  is  produced  by  the  regular  gardeners  to  the 


11 

extent  of  barely  remunerative  prices.  The  average  man,  unskilled  in 
the  growing  of  these  things,  working  with  conditions  not  the  best,  I 
fear,  would  discredit  the  whole  thing.  Satisfactory  crops  of  vege- 
tables as  a  rule  need  enriched  soil  all  to  themselves.  It  seems  that  the 
constant  going  over  the  land  with  irrigation  and  tramping  over  it 
gathering  vegetables,  does  not  leave  the  land  in  good  physical  con- 
dition." 

SUMMARY 

Remember,  in  intercropping,  that  two  crops  are  being  raised  and 
that  each  one  needs  the  same  sort  of  attention  as  if  it  were  growing 
separately. 

Rely  on  the  most  successful  general  farming  practice  of  the  com- 
munity for  choice  of  crops  and  cultural  methods.  Crops  which  are  not 
successful  in  open  field  farming  in  the  district  will  be  failures  as 
intercrops. 

Arrange  for  the  upkeep  of  the  organic  matter  content  of  the  soil 
through  the  use  of  legumes  to  be  turned  under  and  the  use  of  other 
forms  of  organic  matter. 

Avoid  crops  which  necessitate  tramping  of  wet  ground  or  which 
call  for  excessive  irrigations. 

Plant  orchards  to  beans  (unless  some  other  crop  is  definitely  better 
adapted)  wherever  there  is  a  reasonable  expectation  that  the  crop 
wiU  pay  for  the  additional  expenditures. 


STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 


Appendix  to   Viticultural 


REPORTS 

1897.  Resistant  Vines,   their  Selection,    Adaptation,    and   Grafting. 

Report  for  1896. 

1902.  Report  of  the   Agricultural   Experiment   Station   for    1898-1901. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903—04. 

1914.  Report  of  the  College  of  Agriculture  and  the  Agricultural   Experiment   Station. 

1915.  Report  of  the  College  of  Agriculture  and  the  Agricultural  Experiment   Station. 

1916.  Report  of  the  College  of   Agriculture   and  the  Agricultural  Experiment   Station. 

1917.  Report  of  the  College  of  Agriculture  and  the   Agricultural   Experiment   Station. 


No. 

230. 
241. 

242. 
246. 
248. 

250. 
251. 


252. 
253. 

255. 
257. 
261. 

262. 

263. 
264. 
265. 
266. 

267. 
268. 
270. 


BULLETINS 

No. 

Etiological  Investigations.  271. 

Vine  Pruning  in  California,  Part  I.  272. 

Humus  in  California  Soils.  273. 

Vine  Pruning  in  California,   Part  II. 
The  Economic  Value  of  Pacific   Coast  274. 

Kelps. 
The  Loquat.  275. 

Utilization  of  the  Nitrogen  and  Organic 

Matter    in    Septic    and    Imhoff   Tank  2  76. 

Sludges.  277. 

Deterioration   of   Lumber.  278. 

Irrigation   and   Soil   Conditions   in  the  2  79. 

Sierra  Nevada  Foothills,  California.  280. 

The  Citricola  Scale. 

New  Dosage  Tables.  282. 

Melaxuma    of    the    Walnut,     "Juglans 

regia."  283. 

Citrus   Diseases   of   Florida   and   Cuba  284. 

Compared  with  Those>  of   California.  285. 

Size  Grades  for  Ripe  Olives.  286. 

The  Calibration  of  the  Leakage  Meter.  288. 

Cottony   Rot  of   Lemons   in   California. 
A  Spotting  of  Citrus  Fruits  Due  to  the  290. 

Action  of  Oil  Liberated  from  the  Rind. 
Experiments  with  Stocks  for  Citrus.  291. 

Growing  and  Grafting  Olive  Seedlings. 
A  Comparison  of  Annual  Cropping,  Bi- 
ennial Cropping,  and  Green  Manures 

on  the  Yield  of  Wheat. 


Feeding  Dairy  Calves  in  California. 

Commercial  Fertilizers. 

Preliminary  Report  on  Kearney  Vine- 
yard Experimental  Drain. 

The  Common  Honey  Bee  as  an  Agent 
in  Prune  Pollination. 

The  Cultivation  of  Belladonna  in  Cali- 
fornia. 

The  Pomegranate. 

Sudan  Grass. 

Grain   Sorghums. 

Irrigation  of  Rice  in  California. 

Irrigation  of  Alfalfa  in  the  Sacramento 
Valley. 

Trials  with  California  Silage  Crops  for 
Dairy  Cows. 

The  Olive  Insects  of  California. 

Irrigation  of  Alfalfa  in  Imperial  Valley. 

The  Milch  Goat  in  California. 

Commercial  Fertilizers. 

Potash  from  Tule  and  the  Fertilizer 
Value  of  Certain  Marsh  Plants. 

The  June  Drop  of  Washington  Navel 
Oranges. 

The  Common  Honey  Bee  as  an  Agent 
in  Prune  Pollination.      (2nd  report.) 


No. 
113. 
114. 
115. 

121. 

124. 
126. 
127. 
128. 
129. 
131. 
133. 
135. 
136. 
137. 
138. 
139. 


142. 

143. 

144. 
147. 
148. 
150. 
151. 
152. 

153. 

154. 

155. 


Correspondence  Courses  in  Agriculture. 

Increasing  the  Duty  of  Water. 

Grafting  Vinifera  Vineyards. 

Some  Things  the  Prospective  Settler 
Should    Know. 

Alfalfa   Silage  for  Fattening  Steers. 

Spraying  for  the  Grape  Leaf  Hopper. 

House  Fumigation. 

Insecticide  Formulas. 

The  Control  of  Citrus  Insects. 

Spraying  for  Control  of  Walnut  Aphis. 

County  Farm  Adviser. 

Official  Tests  of  Dairy  Cows. 

Melilotus  Indica. 

Wood  Decay  in  Orchard  Trees. 

The  Silo  in  California  Agriculture. 

The  Generation  of  Hydrocyanic  Acid 
Gas  in  Fumigation  by  Portable  Ma- 
chines. 

The  Practical  Application  of  Improved 
Methods  of  Fermentation  in  Califor- 
nia Wineries  during  1913  and  1914. 

Practical  and  Inexpensive  Poultry  Ap- 
pliances. 

Control  of  Grasshoppers  in  Imperial 
Valley. 

Oidium  or  Powderv  Mildew  of  the  Vine. 

Tomato  Growing  in  California. 

"Lungworms." 

Round  Worms   in  Poultry. 

Feeding  and  Management  of  Hogs. 

Some  Observations  on  the  Bulk  Hand- 
ling of  Grain  in  California. 

Announcement  of  the  California  State 
Dairv  Cow  Competition,    1916-18. 

Irrigation  Practice  in  Growing  Small 
Fruits  in  California. 

Bovine  Tuberculosis. 


CIRCULARS 

No. 
156. 
157. 
158. 
160. 
161. 
162. 


164. 
165. 

166. 
167. 
168. 

169. 

170. 

172. 
174. 
175. 

176. 

177. 
181. 


183. 
184. 
185. 

186. 
187. 
188. 
190. 
191. 


How  to  Operate  an  Incubator. 

Control  of  the  Pear  Scab. 

Home  and  Farm  Canning. 

Lettuce  Growing  in  California. 

Potatoes  in  California. 

White    Diarrhoea    and    Coccidiosis    of 

Chicks. 
Small  Fruit  Culture  in  California. 
Fundamentals    of    Sugar    Beets    under 

California   Conditions. 
The  County  Farm  Bureau. 
Feeding  Stuffs  of  Minor  Importance. 
Spraying  for  the  Control  of  Wild  Morn- 
ing-Glory within  the  Fog  Belt. 
The  1918  Grain  Crop. 
Fertilizing     California     Soils     for     the 

1918  Crop. 
Wheat  Culture. 
Farm  Drainage   Methods. 
Progress  Report  on  the  Marketing  and 

Distribution   of   Milk. 
Hog      Cholera      Prevention      and     the 

Serum  Treatment. 
Grain  Sorghums. 
Control     of     the     California     Ground 

Squirrel. 
Extending  the  Area  of  Irrigated  Wheat 

in   California  for   1918. 
Infectious  Abortion  in  Cows. 
A  Flock  of  Sheep  on  the  Farm. 
Beekeeping   for   the   Fruit-Grower   and 

Small  Rancher,  or  Amateur. 
Poultry  on  the  Farm. 
Utilizing  the  Sorghums. 
Lambing  Sheds. 

Agriculture  Clubs  in  California. 
Pruning  the  Seedless  Grapes. 


